The George Washington University Biostatistics Center proposes to continue as the Coordinating Center for the Diabetes Prevention Program Outcomes Study (DPPOS). This application is companion to the Clinical Centers'application. The Diabetes Prevention Program (DPP), a multi-center controlled clinical trial in a multiracial population of overweight persons with impaired glucose tolerance, established the efficacy of a life-style intervention aimed at a modest degree of weight loss and increased moderate-intensity activity, and of metformin in decreasing the development of diabetes by 58 and 31%, respectively. The DPPOS, a 10- year follow-up, was funded in 2002 for a five-year period with the understanding that it would require refunding via competitive renewal. The overarching goal of DPPOS was to study whether the relatively shortterm benefits of delaying diabetes demonstrated in the DPP would translate into a more long-lasting impact that would reduce the public health burden of the diabetes epidemic. Specifically, DPPOS had the following major goals: 1) to determine the effects of DPP interventions on the long-term microvascular and cardiovascular disease (CVD) complications, atherosclerosis and CVD risk factors;2) to examine the long-term effects and durability of prior DPP interventions on further diabetes development;and 3) to describe the incidence of long-term complications and their risk factors in new onset type 2 diabetes and IGT. To date, after 10 years of DPP/DPPOS, 93% of the DPPOS cohort attends annual follow-up visits. A durable effect of diabetes prevention associated with the life-style and metformin interventions has been demonstrated with 36 and 19% reductions in diabetes incidence, respectively, compared with the placebo group. Interim analyses also reveal significant reductions in CVD risk factors in the intervention groups, with decreased utilization of medications. The development of diabetes is associated with an increased frequency of retinopathy and microalbuminuria. The development of diabetes is associated with an increased frequency of retinopathy and microalbuminuria. This application is designed to support completing the second five-years of DPPOS focusing on complications that require more time to develop. RELEVANCE: The Diabetes Prevention Program (DPP) and first 5 years of the DPP Outcome Study (DPPOS) have demonstrated that a lifestyle intervention program aimed at weight loss, and metformin, prevent diabetes development over a 10 year period. Completion of DPPOS will examine the impact of diabetes prevention on long-term complications affecting the eye, kidney, nerves and heart, and remains critical to public health.